The invention concerns an automatic analyzer system including a rack supply unit capable of containing sample racks, an analyzer unit for testing an analysis item of a sample sampled from a sample container contained in a sample rack, and a transfer line for moving a sample rack from the buffer unit to a position corresponding to the analyzer unit.
A system of the above mentioned kind is described in European Patent Application EP-A-0856736 A2. This known system comprises two separate transfer lines: a first transfer line for bringing a sample rack from a rack supply unit to an analyzer unit, and a second transfer line for bringing racks containing samples to be re-examined from the output end of the first transfer line back to the input end of the a first transfer line. In addition to the rack supply unit, this known system comprises a stand-by unit for temporarily storing racks containing samples having a probability of being re-examined, a collecting unit for storing racks containing samples which do not have to be re-examined and which should leave the system, first mechanical means for transferring a sample rack from the rack supply unit to the input end of the first transfer line, second mechanical means for transferring a sample rack from the output end of the first transfer line to the input of the stand-by unit, third mechanical means for transferring a sample rack from the output end of the stand-by unit either to the input end of the second transfer line or to the input end of the collecting unit. The stand-by unit is located close to the output end of the first transfer line, and the collecting unit is adjacent to the stand-by unit. As can be appreciated from the above description of the prior art system described in EP-A-0856736 A2, such a system is rather complex and therefore relatively expensive.
The aim of the invention is therefore to provide a system of the above mentioned kind which has a more simple structure and which is therefore less expensive, and which makes it possible however transport a sufficient number of samples per time unit within such a system.
According to the invention, this aim is achieved with an automatic analyzer system comprising
(a) a rack supply unit capable of containing sample racks, the rack supply unit including
(a.1) a rack input device for introducing sample racks into the rack supply unit,
(a.2) a rack output device for removing sample racks from the rack supply unit,
(a.3) a buffer unit for storing unprocessed racks before they are transferred from the rack supply unit to a position corresponding to an analyzer unit, and for storing also already processed racks which contain samples having a probability of being reexamined, and
(a.4) means for moving racks from the rack input device and the rack output device to the buffer unit and vice versa;
(b) at least one analyzer unit for testing an analysis item of a sample sampled from a sample container contained in a sample rack, the buffer unit being so arranged as,to be interposed between the input/output unit and the at least one analyzer unit,
(c) a single transfer line for moving a sample rack from the buffer unit to a position corresponding to the at least one analyzer unit and for moving the sample rack from the position back to the buffer unit,
(d) means for moving the sample rack in opposite senses along said single transfer line, and
(e) means for directing a sample rack from the rack input device and the rack output device to the buffer unit or vice versa, and
(f) means for directing a sample rack from the buffer unit to the at least one analyzer unit or vice versa.
The main advantages of a system according to the invention over the above mentioned prior art are a much simpler structure of the means for transporting sample racks and therefore a corresponding reduction of the cost of such means.